BGA (Ball Grid Array)

Notes

Introduced commercially in the early 1990s and now the default body style for processors, FPGAs and high pin count ASICs.

Overview

A BGA (ball grid array) is a surface-mount chip package whose connections to the circuit board are solder balls arranged in a grid across its underside. Using the whole bottom face instead of just the edges lets a package carry hundreds or thousands of connections with short electrical paths, which is why processors, memory and many ASICs use it. The name covers a large family, from small fine-pitch memory packages to large flip chip packages for server processors.

How it works

Inside a BGA, the die sits on a substrate, usually a multilayer laminate with copper routing for signals, power and ground. In a wire-bonded BGA the die faces up and fine wires connect it to the substrate, with a moulded cap on top. In a flip chip BGA (FCBGA) the die is turned face down and joined to the substrate by bumps, and the package may be left open or fitted with a lid. The substrate fans the die's connections out to an array of pads on its underside, and a solder ball is attached to each pad.

On the board, the package is placed onto matching copper pads and heated in a reflow oven. The balls melt and surface tension pulls the package into alignment before the joints cool. In one large assembler's catalogue, ball pitches run from 1.5 mm down to 0.4 mm and body sizes from 10 mm to more than 60 mm, the largest being flip chip packages.

The trade-offs follow from the hidden joints. Short balls cannot flex like leads, so differences in thermal expansion between package and board, and vibration, can crack them; underfill is sometimes added to share the strain. The joints cannot be seen after soldering, so they are checked with X-ray, boundary scan or destructive dye-and-pry testing, and a faulty part needs a rework station to remove and replace.

Examples

• A plastic BGA with a wire-bonded die on a laminate substrate and balls at 1.0 mm pitch, used for a microcontroller or ASIC.
• A large lidded flip chip BGA carrying a server processor or AI accelerator.
• Fine-pitch BGA memory packages soldered onto a memory module.
• Package-on-package, where a memory BGA is soldered directly on top of a processor package in a phone.
• X-ray inspection of a board after reflow to find voids or bridges in BGA joints that cameras cannot see.

Why it matters

The BGA is one of the most common packages for complex chips, so its ball count, pitch and size shape board layer counts, assembly yields and long-term reliability. Package designers, substrate engineers, board layout engineers, assembly process engineers and reliability engineers all work with it, and a package choice made early in a project constrains the board technology a customer must use.

In the chip lifecycle, the BGA type is chosen at architecture, the ballout and substrate are designed alongside the chip, packages are built at the OSAT, and board-level reliability testing forms part of qualification.

It matters most to: Package and Board-Level Reliability Engineer, Package Design Engineer, Package Layout & Substrate Design Engineer, PCB Layout Engineer, SMT Process Engineer

Common confusions

Not the same as LGA (land grid array)

An LGA has flat contact pads on its underside instead of solder balls, and is often fitted in a socket rather than soldered directly.

Not the same as flip chip

Flip chip describes how the die is joined to the substrate inside the package. BGA describes how the package is joined to the board. An FCBGA uses both.

Not the same as PGA (pin grid array)

A pin grid array has pins instead of balls and usually plugs into a socket. The BGA developed from it as pin counts and spacing became limiting.

Sources

1. PBGA/TEPBGA (Plastic Ball Grid Array) (opens in a new tab), Amkor Technology, 2026-10-22
2. FCBGA (Flip Chip Ball Grid Array) (opens in a new tab), Amkor Technology, 2026-10-22
3. Ball grid array (Wikipedia) (opens in a new tab), Wikimedia Foundation, 2026-10-22

Related terms

• FCBGA
• LGA
• Solder ball
• Ballout

Where it appears on the Hub

Used on 10 pages of the Hub. In each group, the pages that mention it most come first.